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TSKS01 Digital kommunikation

Course program autumn 2011

Innehåll

       

Separata sidor

Introduction         Introduction
Time         Time
Teachers and Staff         Teachers and Staff
Litterature         Litterature
Examination         Examination
Lectures         Lectures
Tutorials         Tutorials
Specification of course aims         Specification of course aims

1. Introduction

TSKS01 Digital Communication is a prerequisite course for telecom related courses in the fourth year (e.g. Data compression, Image and audio coding, Digital Communication, c.c., Radio communication, Information networks and Error-Correcting Codes). This course is supposed to be both an introduction for those planning to follow some of the courses above, and it is also supposed to be an orientation in telecom techniques for those not planning to follow any of the above courses.

If you are reading a paper copy of this course program:
There is more information on the course webpage: //www.commsys.isy.liu.se/TSKS01. Among other things, this course information is there.

2. Time

Lectures: 12 × 2 h = 24 h
Tutorials: 12 × 2 h = 24 h
Laborations: 2 × 4 h = 8 h

3. Teachers and Staff

During autumn 2011, the following people are engaged in this course.

Lecturer, problem classes and examiner: Mikael Olofsson
mikael@isy.liu.se
tel. 281343
Tutorials: <Okänt användarnamn: tvk>
tvk@isy.liu.se
tel. 282653
Grupp_A.
  <Okänt användarnamn: mirsad>
mirsad@isy.liu.se
tel. 281340
Grupp_B.
Administrator: <Okänt användarnamn: sanna>
sanna@isy.liu.se
tel. 281325

All persons above are in Building B, top floor, Corridor A, between Entrances 27 and 29.

4. Litterature

The main material is the following, and you can buy it in the book store Bokakademin.


Textbook.

  • Mikael Olofsson, Introduction to Digital Communication.
  • Introduction to Digital Communication - Problems.

There will also be some extra material made available from the course web site later on.

In case you have the following formula handbooks, it might come in handy in certain problem classes. It is also allowed to bring to the exam.

  • Mikael Olofsson: Tables and Formulas for Signal Theory (course material in Signal Theory 2008 or 2009).

If you are following TSDT14 Signal Theory in parallel with this course, you should already have one.

5. Examination

The examination consists of two parts, that are reported separately to LADOK:

  • TEN1 (5 hp), which is a traditional written exam, and
  • LAB1 (1 hp), which consists of two lab assignments which is examined by oral reporting before leaving the lab.
5.1 Written Exam (TEN1)

The exam is a written exam. It consists of three parts, an introductory task, a question part and a problem part.

Totally, you can get at most 15 points. Allowed aids during the exam: Paper, pencil, rubber, pocket calculator, and the Tables & Formulas booklet from Signal Theory.

5.1.1 The introductory task

No points are given for the introductory task. It has to be solved correctly to pass the exam. It examines the following aim:

  • The student should be able to reliably perform standard calculations regarding digital modulation, binary (linear) codes for error control and source coding.
5.1.2 The question part

The question part consists of two questions, where you are asked to elaborate on (or explain) topics of this course. These questions can give you at most five points each. You need at least three points from this part of the exam to pass. This part examines the following aims:

  • The student should be generally aquainted with modern communication, especially digital communication, i.e. be able to briefly describe several communication techniques.
  • The student should be able to briefly account for some common channel models, especially for cables, radio channels and optical channels.
  • The student should be able to describe problems that arise in telecommunication situations, using own words, and be able to describe, and in a relevant way, compare methods to counteract those problems.
  • The student should be able to account for the connection between different concepts in the course in a structured way using adequate terminology.
5.1.3 The problem part

The problem part consists of four traditional problems. These problems can give you at most five points each. You need at least six points from this part of the exam to pass. This part examines the following aim:

  • The student should be able to, with some precision, analyze and compare various choices of digital modulation methods and coding methods in terms of error probabilities, minimum distances and related concepts.
5.1.4 Grading

The grade on the exam, and also on the course, is based on the total number of points obtained in the question and problem parts.

Grading limits (Swedish grades):

  • Grade 3 (pass): Intro task correct and 14 points
  • Grade 4: Intro task correct and 19 points
  • Grade 5: Intro task correct and 24 points

Totally, you can get at most 30 points.

5.2 Laborations (LAB1)

The laborations examine the aim

  • be able to implement such communication systems that are treated in the course in block form and empirically evaluate them.

The first laboration takes place during the first half of the course, i.e. HT1. The second laboration takes place during the second half of the course, i.e. during HT2. They will be based on a Lab-memo that will be made available at the course web site.

Both laborations are done in the Research lab of the Division of Communication Systems. It is located on the top floor of Building B, in corridor D between entrances 25-27, close to 27.

6. Lectures

Please observe that the following schedule should be interpreted as an indication about approximately when different topics are treated.

Lecture n:o Chapter Main topic Part
1 1 Introduction Course plan, applications, prerequisites.
--- Repetition Signals and systems, primarily Fourier transforms.
4.2 Channel models Cable channels
4.4 Channel models Optical channels.
2 --- Repetition Probability theory.
3.1-3.3 Random signals Introduction to stochastic processes.
3 3.4-3.7 Random signals Filtering and sampling.
4 4.1 Channel models Thermal noise.
4.3 Radio channels.
5 --- Lab preparation Introduction to software-defined radio in general, and GNU Radio specifically.
6 2 Representation Complex baseband representation of deterministic passband signals.
7 5 Digital modulation The vector model. Vector spaces, geometrical interpretation of signals, representation of white Gaussian noise, orthogonalization.
8 6 Digital modulation Detection of signals disturbed by white gaussian noise. Correlation receivers, matched filter receivers. ML-detection, MAP-detection. Union bound, nearest-neighbour approximation.
9 7 Digital modulation Modulation. Symbol error probability - bit error probability. Digital modulation techniques, On-off-keying, PSK, FSK, QAM, OFDM.
10-11 8 Channel Coding Error correcting codes, dimension, redundancy, rate. Linear codes, repetition codes, Hamming codes, product codes. Possibly cyclic codes and CRC codes.
12 9 Source Coding Sources without memory - sources with memory, Markov sources. Tree codes, Krafts inequality, Huffman codes, run length coding, arithmetic coding.

My recommendation is that you read the corresponding part of the course material through once before each lecture. If not, the lecture may not be as useful to you as you might wish.

7. Tutorials

The tutorials are supposed to be opportunities for discussion about solving problems. Below is a suggestion for problems to treat in each tutorial. You should study those problems in advance in order to benefit the most from those tutorials.

Number Main topic Part Problems
1 Repetition Signals & Systems 3.5
Channel Models Extra tasks
2 Stochastics Repetition stochastic variables 1.1, 1.3, 1.4, 1.6, 1.9 (1.2, 1.5, 1.7, 1.8)
Stochastic processes 2.1, 2.2
3 Representation Baseband representation Extra tasks
4 Digital modulation The vector model 3.2, 3.3, 3.4 (3.1, 3.6)
Extra tasks
5 Detection 4.1, 4.2, 4.3, 4.7, 4.11 (4.10)
6 Detection 4.4, 4.5, 4.6, 4.8, 4.9 (4.12, 4.13)
7 Detection 5.1, 5.2, 5.5, 5.10
8 Modulation 5.3, 5.4, 5.6, 5.7, 5.12 (5.14)
9 Error probabilities 5.8, 5.9, 5.11, 5.15a (5.13, 5.15b)
10 Channel Coding Analyzing codes 6.1, 6.2, 6.5, 6.6, 6.8, 6.9
11 Channel Coding Structure of codes 6.3, 6.4, 6.7, 6.10, 6.12 (6.11)
12 Source Coding 7.1, 7.2, 7.3, 7.4, 7.5, 7.8 (7.6, 7.7, 7.9)

 

Questions about the problems are welcome before the corresponding tutorial. Send them by email to your tutorial teacher <Okänt användarnamn: mirsad>  or <Okänt användarnamn: tvk>. In that way you can help your teacher to plan the tutorials.

8. Specification of course aims

8.0 Contents
8.1 General

One demand on examiners that is related to the Bologna process is that the course syllabus in the study guide (studiehandboken) must contain a few aims, and it must be clear how those aims are tested in the exam. All those aims must be tested at every examination opportunity. A consequence of this is that those aims are given a fairly vague formulation, and that those aims rather are section titles in a more traditional aim description.

For that reason, this page contains a specification of the aims in the study guide and how they are examined, grouped according to in what part of the exam they are treated.

8.2 The introductory task

This task tests basic knowledge and abilities, i.e. the following aim.

  • The student should be able to reliably perform standard calculations regarding digital modulation, binary (linear) codes for error control and source coding.

One demand for passing the exam is that this task is treated completely correct. This task is actually two tasks, one from each of two out of the following three areas.

  • Digital modulation.
    Simple error probability calculations for binary modulation forms, not necessarily standard choices, and only based on vector representations. So, this is primarily about distances between vectors. There will be no need for time domain descriptions.
  • Binary codes for error control.
    Primarily simple parameter calculations. For example: Given length, dimension and minimum distance of a code, determine its error correction or error detection capabilities Or: Given a matrix description of a linear code (generator or parity check matrices), determine the length and dimension of the code. You may be asked to determine the minimum distance of a code, but in that case only for very small codes.
  • Source coding.
    Determining a Huffman code for a small alphabet, or perform run-length encoding of an explicit binary sequence. You will not be asked to determine any quality measures of source codes here.

See also:

8.3 The question part

Tasks number two and three examine the following aims, and they are tested by sample questions.

  • The student should be generally aquainted with modern communication, especially digital communication, i.e. be able to briefly describe several communication techniques.
    This deals with more or less everything that is treated in the compendium, but on a general level. This is not about detail, but about principle descriptions. E.g. being able to describe PSK.
  • The student should be able to briefly account for some common channel models, especially for cables, radio channels and optical channels.
    This is about accounting for things like thermal noise, linear time (in)variant filtering, multipath transmission, fading, primarily in general terms.
  • The student should be able to describe problems that arise in telecommunication situations, using own words, and be able to describe, and in a relevant way, compare methods to counteract those problems.
    The problem at hand is primarily noise.
  • The student should be able to account for the connection between different concepts in the course in a structured way using adequate terminology.
    This is about connections between noise and various quality measures, the geometrical interpretation of digital modulation and connections between parameters for codes for error control.

See previous exams for examples on what those tasks can be like.

These two tasks are given at most five points per task, i.e. totally at most ten points are available in this part. One demand for passing the exam is that you have gotten at least three points from this part.

8.4 The problem part

Tasks number four through seven examine the following aim, and it is tested by sample problems.

  • The student should be able to, with some precision, analyze and compare various choices of digital modulation methods and coding methods in terms of error probabilities, minimum distances and related concepts.
    Those are traditional exam tasks. You should be able to analytically solve given problems from the parts of the course that we treat in problem classes, i.e. the following course parts, and the examination is based on samples from two or three of those parts.
    • Baseband representation of passband signals
      Transformations between different representations of signals, and handling filtering and modulation in those representations.
    • Digital modulation:
      There can be both binary and non-binary modulation schemes here, both standard choices and arbitrary modulation schemes. Typically you need to perform error probability calculations, average energy calculations of maximum energy calculations. It is possible that you are asked to compare two modulation schemes in these terms or to construct a modulation scheme that fulfills some demands.
    • Codes for error control.
      Primarily, we treat linear block codes here, but non-linear codes can also be treated. Those codes are fairly small, and you typically need to analyze them in terms of their parameters, to determine the minimum distance, the weight distribution, the distance distribution, the error correction capability or the error detection capability, of the code. Most often, the starting point is a generator matrix or a parity check matrix, and it may happen that a code is created by modifying a code. Some concepts that you may be able to handle here ar cyclic codes, product codes, duality, syndrome and decoding.
    • Source coding.
      You should be able to create a tree code from given source statistics, using the Huffman algorithm. You should be able to analyze tree codes in terms of compression ratios and redundancy. You should be able to use Krafts inequality to determine if a tree code exists for a given collection of codeword lengths. You should also know and be able to use the concept source extension. Finally, there may be run-length encoding here.

See previous exams for examples on what those tasks can be like. Notice that problems where you are asked to calculate PSDs (Power Spectral Densities) or bandwidths are no longer relevant.

These four tasks are given at most five points per task, i.e. totally at most twenty points are available in this part. One demand for passing the exam is that you have gotten at least six points from this part.

8.5 Grading

To pass the exam, you first and foremost need to fulfil the basic demands on the three parts, i.e. correctly treated introductory task, at least three points from the question part and at least six points from the problem part. If all this is fulfilled, then the exam is graded according to the following grading limits based on the sum of the points obtained from the question part and the problem part.

  • Grade 3 (ECTS C): 14 points.
  • Grade 4 (ECTS B): 19 points.
  • Grade 5 (ECTS A): 24 points.

Totally, you can get at most 30 points on the exam.

8.6 Possibility to improve

The rules regarding the introductory task, that it has to be completely correctly treated, as a partial demand for passing the exam, may seem a bit hard. For that reason we practice the following. If you miss one of the two parts of the introductory task, and if you have fulfilled all other demands for passing the exam, then you are given the opportunity to solve a new task that could have been part of the introductory task.

This is done at the examiners office at a time that you and the examiner agree upon, but it has to be done before the next exam opportunity.

8.7 Laborations

The laborations test the following aim.

  • The student should be able to implement such communication systems that are treated in the course in block form and empirically evaluate them.

Sidansvarig: Mikael Olofsson
Senast uppdaterad: 2019 07 30   10:16